CN101737726B - Light guide unit and backlight module - Google Patents

Abstract

A light guide unit includes a light guide plate and a plurality of cylindrical lenses. The light guide plate has a first surface, a second surface opposite to the first surface, and a light incident surface connecting the first surface and the second surface, wherein the light guide plate further has a plurality of diffusion points located on the second surface. These cylindrical lenses are arranged on the first surface, each cylindrical lens extends along a first direction and has a curved surface bent in a second direction. These cylindrical lenses are arranged along the second direction. The pitch of adjacent diffusion points in the first direction is smaller than the pitch in the second direction. A backlight module using this light guide unit is also proposed.

Description

Light guide unit and backlight module

technical field

The present invention relates to a light source module and its optical elements, and in particular to a backlight module and its light guide unit.

Background technique

FIG. 1 is a schematic cross-sectional view of a conventional backlight module. Referring to FIG. 1 , the conventional backlight module 100 includes a light guide plate 110 , a cold cathode fluorescent lamp (cold cathode fluorescent lamp, CCFL) 120 , a reflector 130 and a diffusion plate 140 . The light guide plate 110 has a first surface 112 , a second surface 114 opposite to the first surface 112 , and a light incident surface 116 connecting the first surface 112 and the second surface 114 . The cold cathode fluorescent lamp 120 is disposed beside the light incident surface 116 and is adapted to emit a light beam 122 toward the light incident surface 116 . Part of the light beam 122 a enters the light guide plate 110 through the light incident surface 116 , and is transmitted to the reflection sheet 130 through the light diffusion effect of the titanium dioxide (TiO ₂ ) dots 114 a on the second surface 114 . The reflection sheet 130 reflects part of the light beam 122 a and makes it pass through the second surface 114 , the first surface 112 and the diffusion sheet 140 in sequence. On the other hand, after entering the light guide plate 110, the partial light beam 122b will be transmitted to the first surface 112 through the light diffusion effect of the titanium dioxide dots 114a, and then the partial light beam 122b will sequentially pass through the first surface 112 and the diffusion sheet 140. The light beam 112 (including partial light beams 112 a and 112 b ) will form a surface light source after passing through the diffuser 140 .

When the titanium dioxide dots 114a are formed on the second surface 114 by screen printing, the size and spacing of the titanium dioxide dots 114a cannot be made very small. Therefore, when the diffusion sheet 140 is not disposed above the light guide plate 110 , the discontinuous bright spots formed by the titanium dioxide dots 114 a will be recognized by naked eyes, and the backlight module 100 cannot form a uniform surface light source.

In order to improve the problem that the discontinuous bright spots are recognized by the naked eye, in the prior art, the diffusion sheet 140 is used to blur the discontinuous bright spots to achieve a shielding effect. However, using one more diffuser 140 will increase the cost and cause light loss.

Contents of the invention

The invention provides a light guide unit, which can reduce the cost and guide light uniformly.

The invention provides a backlight module, which can reduce the cost and can form a uniform surface light source.

An embodiment of the present invention provides a light guide unit, which includes a light guide plate and a plurality of rod lenses. The light guide plate has a first surface, a second surface opposite to the first surface, and a light incident surface connecting the first surface and the second surface, wherein the light guide plate further has a plurality of diffusion grid points located on the second surface. The lenticular lenses are arranged on the first surface, and each lenticular lens extends along a first direction and has a curved surface curved in a second direction. These lenticular lenses are arranged along the second direction. The pitch of the adjacent diffused dots in the first direction is smaller than the pitch in the second direction.

Another embodiment of the present invention provides a backlight module, which includes the above-mentioned light guide unit and a light emitting element. The light emitting element is arranged beside the light incident surface. The light emitting element is suitable for emitting a light beam, which enters the light guide plate through the light incident surface, and transmits to the lenticular lenses through the first surface.

In the light guide unit of the embodiment of the present invention, since the pitch of the diffused dots in the first direction is smaller than the pitch in the second direction, and the light guide unit has a lenticular lens extending along the first direction, the columnar The lens can reduce the width and spacing of the diffused dots in the second direction, so that the naked eye cannot identify the diffused dots after passing through the lenticular lens. In this way, the backlight module of the embodiment of the present invention can form a uniform surface light source.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a conventional backlight module.

FIG. 2A is a three-dimensional schematic diagram of the backlight module according to the first embodiment of the present invention.

FIG. 2B is a schematic cross-sectional view of the backlight module in FIG. 2A along line I-I.

FIG. 2C is a perspective view of the light guide unit in FIG. 2A with its first surface facing forward.

FIG. 3 is a schematic perspective view of a backlight module according to a second embodiment of the present invention.

4 is a perspective view of the light guide unit of the backlight module according to the third embodiment of the present invention with its first surface facing forward.

5 is a perspective view of the light guide unit of the backlight module according to the fourth embodiment of the present invention with its first surface facing forward.

FIG. 6 is a schematic perspective view of a backlight module according to a fifth embodiment of the present invention.

FIG. 7A is a schematic perspective view of a backlight module according to a sixth embodiment of the present invention.

FIG. 7B is a perspective view of the light guide unit in FIG. 7A with its first surface facing forward.

Detailed ways

The following descriptions of various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention can be practiced. The direction terms mentioned in the present invention, such as "up", "down", "front", "rear", "left", "right", etc., are only referring to the directions of the drawings. Accordingly, the directional terms are used to illustrate, not to limit, the invention.

first embodiment

2A is a perspective view of the backlight module of the first embodiment of the present invention, FIG. 2B is a schematic cross-sectional view of the backlight module of FIG. 2A along the I-I line, and FIG. 2C is a light guide unit in FIG. 2A with its first A perspective view with the surface facing forward. Please refer to FIG. 2A to FIG. 2C , the backlight module 200 of this embodiment includes a light guide unit 300 and a light emitting element 210 . The light guide unit 300 includes a light guide plate 310 and several lenticular lenses 320 . The light guide plate 310 has a first surface 312 , a second surface 314 and a light incident surface 316 . The first surface 312 is opposite to the second surface 314 , and the light incident surface 316 connects the first surface 312 and the second surface 314 . The lenticular lenses 320 are disposed on the first surface 312 . Each lenticular lens 320 extends along a first direction D1 and has a curved surface C curved in a second direction D2. In this embodiment, the curved surfaces C of the lenticular lenses 320 are all convex surfaces, such as cylindrical surfaces, elliptical cylindrical surfaces, or convex surfaces of other shapes. In addition, in this embodiment, the first direction D1 is substantially perpendicular to the second direction D2. Furthermore, in this embodiment, the light guide plate 310 and the lenticular lenses 320 are integrally formed, and the first direction D1 is substantially perpendicular to the light incident surface 316 .

In addition, the light guide plate further has a plurality of diffusion points 318 located on the second surface 314 . The pitch P1 of the adjacent diffused dots 318 in the first direction D1 is smaller than the pitch P2 in the second direction D2. In this embodiment, the diffusion dots 318 are, for example, titanium dioxide dots or other materials suitable for light diffusion. However, in other embodiments, the diffused dots can also be concave or convex dots on the second surface 314 . The light emitting element 210 is disposed beside the light incident surface 316 . In this embodiment, the light emitting element 210 is, for example, a CCFL. However, in other embodiments, the light emitting element 210 may also be a light strip composed of several light emitting diodes or other suitable light emitting elements. The light emitting element 210 is suitable for emitting a light beam 212 , the light beam 212 enters the light guide plate 310 through the light incident surface 316 , and transmits to the lenticular lenses 320 through the first surface 312 . Specifically, after the partial light beam 212 a of the light beam 212 entering the light guide plate 310 is transmitted to the diffusion network point 318 , light scattering phenomenon will occur due to the diffusion effect of the diffusion network point 318 . In this embodiment, one side of the second surface 314 may be provided with a reflection unit 220 for reflecting the light beam 212 to the first surface 312, for example, reflecting a part of the light beam 212a that causes light scattering to the first surface 312, wherein The reflective unit 220 is, for example, a reflective sheet. On the other hand, another part of the light beam 212b in the light beam 212 will be scattered to the first surface 312 by the diffusion network point 318 after passing to the diffusion network point 318 .

In the light guide unit 300 of this embodiment, since the lenticular lens 320 has a curved surface C curved in the second direction D2, and the pitch P2 of the diffuser dots 318 in the second direction D2 is larger than the pitch in the first direction D1 Therefore, the lenticular lens 320 can reduce the pitch of the bright spots in the second direction D2 generated by the diffused dots 318 due to the scattered light beam 212 to a level that cannot be recognized by naked eyes. In addition, since the pitch P1 is smaller than the pitch P2, the pitch of the bright spots generated by the diffused dots 318 due to the scattered light beam 212 in the first direction D1 cannot be recognized by naked eyes. For example, the thickness T of the light guide plate 310 is approximately in the range from 0.5 mm to 5 mm, and the pitch A of the lenticular lenses 320 is approximately in the range from 24 microns to 50 microns, that is, the curvature of the curved surface C The radius approximately falls within a range from 12 microns to 25 microns. Estimated according to a simple lens imaging formula, the imaging magnification of the lenticular lens 320 falls within a range from 0.0016 to 0.032. In other words, after imaging through the lenticular lens 320 above the light guide plate 310 , the pitch of the bright spots generated by the diffusion dots 318 in the second direction D2 is only about 1/30th to 1/600th of the original pitch.

In this way, when forming the diffused dots 318 on the light guide plate 310, the screen printing method, which is relatively cheap and has a relatively large spacing between the formed diffused dots, can be used, and the surface light source produced by the backlight module 200 is also less expensive. There is a problem of discrete bright spots being observed by the naked eye of the user. In other words, the light guide unit 300 of this embodiment can lead out the light beam 212 uniformly, and can have lower cost. Therefore, the backlight module 200 of this embodiment can form a uniform surface light source, and can have lower cost. In addition, when a prism sheet (not shown) is to be arranged above the light guide plate 310 to concentrate the surface light source, since the diffused dots 318 have passed through the effect of the lenticular lens 320 and cannot be recognized by the naked eye, the lenticular lens 320 and the prism sheet There may be no diffusion sheet between them, which can further reduce the cost of the backlight module 200 and reduce light loss.

It should be noted that the present invention does not limit the diffused dots 318 to be formed by screen printing. In other embodiments, the diffused dots 318 can also be formed by photolithographic etching process or other etching methods.

In this embodiment, the width W2 of the diffused dots 318 in the second direction D2 increases gradually as the distance from the light incident surface 316 increases. On the other hand, in this embodiment, the width W1 of the diffused dots 318 in the first direction D1 can remain the same. In this way, it is helpful for the light guide plate 310 to transmit the light beam 212 to a place away from the light incident surface 316 , so that the backlight module 200 can provide a relatively uniform surface light source.

second embodiment

FIG. 3 is a schematic perspective view of a backlight module according to a second embodiment of the present invention. Please refer to FIG. 3 , the backlight module 200 a of this embodiment is similar to the above-mentioned backlight module 200 (please refer to FIG. 2A ), and the differences between the two are as follows. In the light guide unit 300a of the backlight module 200a of this embodiment, some of the curved surfaces C1 of these lenticular lenses 320a are convex surfaces, and some of the curved surfaces C1' of these lenticular lenses 320a' are concave surfaces, and these curved surfaces C1 and these curved surfaces C1' Alternately arranged in the second direction D2. In this embodiment, these curved surfaces C1 and these curved surfaces C1' form a one-dimensional sinusoidal surface. However, in other embodiments, the curved surface C1 can also be a cylindrical surface, an elliptical cylindrical surface, or a convex surface of other shapes, and the curved surface C1' can also be a cylindrical concave surface, an elliptical cylindrical concave surface, or a concave surface of other shapes. The light guide unit 300a has similar advantages and functions to the above light guide unit 300 (as shown in FIG. 2A ), which will not be repeated here.

third embodiment

4 is a perspective view of the light guide unit of the backlight module according to the third embodiment of the present invention with its first surface facing forward. Please refer to FIG. 4 , the light guide unit 300 b of the backlight module of this embodiment is similar to the above light guide unit 300 (as shown in FIG. 2C ), and the differences between the two are as follows. In the light guide unit 300b of the present embodiment, the number density of the diffused dots 318 increases gradually as the distance from the light incident surface 316 increases. In this way, the light guide unit 300b can guide the light away from the light incident surface 316, so that the backlight module can provide a uniform surface light source. In addition, in this embodiment, the widths W1' of the diffused dots 318 in the first direction D1 may be substantially the same, and the widths W2' of the diffused dots 318 in the second direction D2 may also be substantially the same.

Fourth embodiment

5 is a perspective view of the light guide unit of the backlight module according to the fourth embodiment of the present invention with its first surface facing forward. Please refer to FIG. 5 , the light guide unit 300 c of the backlight module of this embodiment is similar to the above light guide unit 300 (as shown in FIG. 2C ), and the differences between the two are as follows. In the light guide unit 300c of this embodiment, several diffused dots 318 form several striped patterns 319 . Each strip pattern 319 extends away from the light incident surface 316, and these strip patterns 319 are arranged along a direction parallel to the light incident surface 316. In addition, the width W3 of each strip pattern 319 increases with the distance from the light incident surface 316. Incrementally, this helps the light guide plate 310 to transmit light to a place away from the light incident surface 316, so that the backlight module can provide a uniform surface light source.

fifth embodiment

FIG. 6 is a schematic perspective view of a backlight module according to a fifth embodiment of the present invention. Referring to FIG. 6 , the backlight module 200d of this embodiment is similar to the above-mentioned backlight module 200 (as shown in FIG. 2A ), and the differences between the two are as follows. In the backlight module 200 of this embodiment, the lenticular lenses 320 constitute a lenticular lens plate 330 , and the lenticular lens plate 330 and the light guide plate 310 are formed separately.

Sixth embodiment

FIG. 7A is a perspective view of a backlight module according to a sixth embodiment of the present invention, and FIG. 7B is a perspective view of the light guide unit in FIG. 7A with its first surface facing forward. Please refer to FIG. 7A and FIG. 7B , the backlight module 200 e of this embodiment is similar to the above-mentioned backlight module 200 d , and the differences between the two are as follows. In the backlight module 200e of this embodiment, the first direction D1' (that is, the extending direction of each lenticular lens 320) is substantially parallel to the light incident surface 316, and the second direction D2' (that is, the arrangement of these lenticular lenses 320 direction) is substantially perpendicular to the light incident surface 316 . In addition, the distribution of the diffused dots 318 also changes as the first direction D1' and the second direction D2' change compared with the fifth embodiment. Specifically, in this embodiment, the pitch P1' of the adjacent diffused dots 318 in the first direction D1' is smaller than the pitch P2' in the second direction D2'. In addition, in this embodiment, the width W2" of these diffused dots 318 in the second direction D2' increases gradually as they get away from the light-incident surface 316.

It should be noted that, in other embodiments, the first direction and the second direction may be substantially parallel to and perpendicular to the light-incident surface, respectively, and the number density of diffuse dots increases as the distance from the light-incident surface increases. Alternatively, the first direction and the second direction are substantially parallel to and perpendicular to the light incident surface respectively, and the diffused dots form several stripe patterns as in the fourth embodiment.

To sum up, in the light guide unit according to the embodiment of the present invention, since the lenticular lens has a curved surface in the second direction, and the pitch of the diffusion dots in the second direction is greater than the pitch in the first direction , so the lenticular lens can reduce the spacing in the second direction of the bright spots generated by the diffused dots due to the scattered light beams to a degree that cannot be recognized by naked eyes. In this way, when forming diffused dots on the light guide plate, the less expensive screen printing method can be used, and the surface light source produced by the backlight module will not have the problem of discrete bright spots observed by the naked eye. . In other words, the light guide unit of the embodiment of the present invention can guide the light beam uniformly, and can have a lower cost, so the backlight module of the embodiment of the present invention can form a uniform surface light source, and can have a lower cost .

In addition, when the prism sheet is to be arranged above the light guide plate to make the surface light source more concentrated, since the bright spots generated by the diffused dots have passed through the action of the lenticular lens and cannot be recognized by the naked eye, there is no need to place the prism sheet between the lenticular lens and the prism sheet. Diffusion sheet, which can further reduce the cost of the backlight module.

Although the present invention has been disclosed as described above with the embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection is based on the claims. In addition, any embodiment or claim of the present invention need not achieve all the objects or advantages or features disclosed in the present invention. In addition, the abstract part and the title are only used to assist the search of patent documents, and are not used to limit the scope of rights of the present invention.

List of main symbol names

100, 200, 200a, 200d, 200e: backlight module

110, 310: light guide plate

112, 312: first surface

114, 314: second surface

114a: Titanium dioxide dots

116, 316: incident surface

120: cold cathode fluorescent tube

122, 212: Beam

122a, 122b, 212a, 212b: partial beams

130: reflector

140: Diffuser

210: light emitting element

220: reflection unit

300, 300a, 300b, 300c: light guide unit

318: Diffusion Outlets

319: Strip pattern

320, 320a, 320a': lenticular lens

330: lenticular lens plate

A, P1, P1’, P2, P2’: Pitch

C, C1, C1': Surface

D1, D1': the first direction

D2, D2': the second direction

T: Thickness

W1, W1’, W2, W2’, W2”, W3: Width

Claims (19)

1. light element comprises:

One LGP, the second surface and with a first surface, relative this first surface connects the incidence surface of this first surface and this second surface, and wherein this LGP has more several diffusion sites, is positioned at this second surface; And

Several lens pillars; Be disposed on this first surface; Each this lens pillar extends along a first direction; And have a curved surface that is bent upwards in a second party, those lens pillars are arranged along this second direction, those wherein adjacent diffusion sites in the pitch on this first direction less than the pitch on this second direction.

2. light element as claimed in claim 1, wherein this first direction is perpendicular to this second direction.

3. light element as claimed in claim 1, wherein this LGP and those lens pillars are formed in one, and this first direction is perpendicular to this incidence surface.

4. light element as claimed in claim 1, wherein those lens pillars constitute a column type lens plate, and this column type lens plate and this LGP are moulding separately.

5. light element as claimed in claim 1, wherein those diffusion site width on this second direction are along with increasing progressively away from this incidence surface.

6. light element as claimed in claim 1, wherein the number density of those diffusion sites is along with increasing progressively away from this incidence surface.

7. light element as claimed in claim 1; Wherein those diffusion sites constitute several strip patterns; Each this strip pattern extends toward the direction away from this incidence surface; Those strip patterns are arranged along the direction parallel with this incidence surface, and the width of each this strip pattern is along with increasing progressively away from this incidence surface.

8. light element as claimed in claim 1, wherein those curved surfaces of those lens pillars are all convex surface.

9. light element as claimed in claim 1, wherein those curved surfaces of those lens pillars of part respectively are a convex surface, and partly those curved surfaces of those lens pillars respectively are a concave surface, and those convex surfaces and those concave surfaces are alternately arranged on this second direction.

10. module backlight comprises:

One light element comprises:

One LGP, the second surface and with a first surface, relative this first surface connects the incidence surface of this first surface and this second surface, and wherein this LGP has more several diffusion sites, is positioned at this second surface; And

Several lens pillars; Be disposed on this first surface; Each this lens pillar extends along a first direction; And have a curved surface that is bent upwards in a second party, those lens pillars are arranged along this second direction, those wherein adjacent diffusion sites in the pitch on this first direction less than the pitch on this second direction; And

One light-emitting component is disposed at by this incidence surface, and wherein this light-emitting component is suitable for sending a light beam, and this light beam can get in this LGP via this incidence surface, and is passed to those lens pillars via this first surface.

11. module backlight as claimed in claim 10, wherein this first direction is perpendicular to this second direction.

12. module backlight as claimed in claim 10, wherein this LGP and those lens pillars are formed in one, and this first direction is perpendicular to this incidence surface.

13. module backlight as claimed in claim 10, wherein those lens pillars constitute a column type lens plate, and this column type lens plate and this LGP are moulding separately.

14. module backlight as claimed in claim 10, wherein those diffusion site width on this second direction are along with increasing progressively away from this incidence surface.

15. module backlight as claimed in claim 10, wherein the number density of those diffusion sites is along with increasing progressively away from this incidence surface.

16. module backlight as claimed in claim 10; Wherein those diffusion sites constitute several strip patterns; Each this strip pattern extends toward the direction away from this incidence surface; Those strip patterns are arranged along the direction parallel with this incidence surface, and the width of each this strip pattern is along with increasing progressively away from this incidence surface.

17. module backlight as claimed in claim 10, wherein those curved surfaces of those lens pillars are all convex surface.

18. module backlight as claimed in claim 10, wherein those curved surfaces of those lens pillars of part respectively are a convex surface, and partly those curved surfaces of those lens pillars respectively are a concave surface, and those convex surfaces and those concave surfaces are alternately arranged on this second direction.

19. module backlight as claimed in claim 10 more comprises a reflector element, is disposed at a side of this second surface, in order to this beam reflection to this first surface.

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